1. Field of the Invention
The present invention relates to a method of manufacturing a thin-film semiconductor and a semiconductor device using the thin-film semiconductor. A thin-film transistor or a thin-film diode can be given as a device using a thin-film semiconductor to which the present invention disclosed in this specification is available.
2. Description of the Related Art
Up to now, there has been known a technique by which a thin-film transistor is formed on the surface of a glass substrate or a quartz substrate, a glass strain point of which is about 700.degree. C. at the highest, through the vapor phase method or the like, and a thin-film transistor is manufactured using the thin-film semiconductor. There has been known a technique using an amorphous silicon film or a crystalline silicon film as the thin-film semiconductor.
In particular, a method of using the crystalline silicon film enables a high characteristic to be obtained. As a method of manufacturing the crystalline silicon film, there has been known a method of crystallizing, by heating, the amorphous silicon film formed on the glass substrate or the quartz substrate through plasma CVD or low pressure thermal CVD.
Also, as a method of lowering a heating temperature, there has been known a technique which has been disclosed in Japanese Patent Unexamined Publication No. Hei 6-244104. The technique is to reduce a heating temperature and a heating time required for the crystallization of the amorphous silicon film, using nickel, platinum, etc., which are a metal element that promotes the crystallization of silicon.
The thin-film transistor obtained by using that method can obtain the high characteristic, but suffers from problems, for example, as stated below.
The dispersion of the characteristics of the thin-film transistor obtained is large.
The characteristics of the thin-film transistor obtained are liable to be deteriorated.
An off-current value is large.
It is presumed that those problems are mainly caused by the junctions of a source and a channel, and also a drain and a channel, or a metal silicide existing in the vicinity of those junctions. In other words, it is presumed that those problems are caused by the fact that the metal silicide existing in the semiconductor is the trap level or the recombination center of electrons with holes.